Photographing devices such as video surveillance equipment, often need to measure an ambient brightness value or ambient brightness level. Accordingly, when the brightness is relatively low, the infrared light fill-in device on the video surveillance equipment may be turned on, and the video surveillance equipment may take black and white images. Thus, the recognizable degree of the images may be enhanced/increased.
Currently, conventional video surveillance equipment often use photosensitive devices contained in the video surveillance equipment to measure the ambient brightness value. The photosensitive devices often include photosensitive resistors, photosensitive diodes, or photosensitive sensors.
However, because photosensitive devices are optical devices, which are highly demanding on the design of the product structures and the manufacturing precision of the products. Sometimes, the same type of video surveillance equipment produced by the same manufacturer have different measurement results of the same ambient, and thus a relatively high measurement error occurs among these video surveillance equipment. As a result, the uniformity of the products may be relatively low. In addition, a video surveillance equipment often requires the measured ambient brightness value or ambient brightness level to be lower than a preset threshold value to turn on the light fill-in device. The light emitted by an infrared light fill-in device may also include visible light, which can cause interference to the measurement of the photosensitive device. As a result, the accuracy of the measurement may be relatively low.
The disclosed methods and devices are directed to solve one or more problems set forth above and other problems.